SofQWPolygon dialog.
Table of Contents
| Name | Direction | Type | Default | Description |
|---|---|---|---|---|
| InputWorkspace | Input | MatrixWorkspace | Mandatory | Reduced data in units of energy transfer DeltaE. The workspace must contain histogram data and have common bins across all spectra. |
| OutputWorkspace | Output | MatrixWorkspace | Mandatory | The name to use for the q-omega workspace. |
| QAxisBinning | Input | dbl list | Mandatory | The bin parameters to use for the q axis (in the format used by the Rebin v1 algorithm). |
| EMode | Input | string | Mandatory | The energy transfer analysis mode (Direct/Indirect). Allowed values: [‘Direct’, ‘Indirect’] |
| EFixed | Input | number | 0 | The value of fixed energy:  (EMode=Direct) or  (EMode=Indirect) (meV). Must be set here if not available in the instrument definition. |
| ReplaceNaNs | Input | boolean | False | If true, all NaN values in the output workspace are replaced using the ReplaceSpecialValues algorithm. |
| EAxisBinning | Input | dbl list | The bin parameters to use for the E axis (optional, in the format used by the Rebin v1 algorithm). |
Converts a 2D workspace in units
of spectrum number/energy transfer to
the intensity as a function of momentum transfer
and energy transfer 
.
The rebinning is done as a weighted sum of overlapping polygons.
The polygon in 
space is calculated from the
energy bin boundaries and the detector scattering angle 
.
The detectors (pixels) are assumed to be uniform, and characterised
by a single angular width 
. The signal and error
of the rebinned data (in space) is then the
sum of the contributing pixels in each bin weighted by their fractional
overlap area. Unlike the more precise SofQWNormalisedPolygon v1
algorithm, these fractional weights are not thereafter retained in the
workspace produced by this algorithm.
See SofQWCentre v1 for centre-point binning. Alternatively, see SofQWNormalisedPolygon v1 for a more complex and precise (but slower) binning strategy, where the actual detector shape is calculated to obtain the input polygon.
Example - simple transformation of inelastic workspace:
# create sample inelastic workspace for MARI instrument containing 1 at all spectra values
ws=CreateSimulationWorkspace(Instrument='MAR',BinParams='-10,1,10')
# convert workspace into MD workspace
ws=SofQWPolygon(InputWorkspace=ws,QAxisBinning='-3,0.1,3',Emode='Direct',EFixed=12)
print("The converted X-Y values are:")
Xrow=ws.readX(59);
Yrow=ws.readY(59);
line1= " ".join('! {0:>6.2f} {1:>6.2f} '.format(Xrow[i],Yrow[i]) for i in range(0,10))
print(line1 + " !")
line2= " ".join('! {0:>6.2f} {1:>6.2f} '.format(Xrow[i],Yrow[i]) for i in range(10,20))
print(line2 + " !")
print('! {0:>6.2f} ------- !'.format(Xrow[20]))
Output:
The converted X-Y values are:
! -10.00 12.79 ! -9.00 17.63 ! -8.00 17.86 ! -7.00 18.12 ! -6.00 18.46 ! -5.00 18.69 ! -4.00 19.24 ! -3.00 19.67 ! -2.00 18.49 ! -1.00 12.00 !
! 0.00 17.08 ! 1.00 22.32 ! 2.00 23.26 ! 3.00 24.46 ! 4.00 25.96 ! 5.00 21.96 ! 6.00 25.10 ! 7.00 33.65 ! 8.00 35.54 ! 9.00 43.86 !
! 10.00 ------- !
Categories: Algorithms | Inelastic\SofQW
C++ source: SofQWPolygon.cpp (last modified: 2018-03-08)
C++ header: SofQWPolygon.h (last modified: 2016-04-16)